Crosslaying machine

ABSTRACT

A METHOD FOR EFFECIENTLY HANDLING AND CROSSLAYING WEBS OF SUBSTANTIALLY ALIGNED LIGHT WEIGHT FIBERS IN THE PRODUCTION OF NONWOVEN MATERIALS INCORPORATING SUCH CROSSLAID FIBERS FOR TWO-DIMENSIONAL STRENGTH. WEBS OF SUBSTANTIALLY ALIGNED FIBERS ARE DEPOSITED ON INDIVIDUAL MOVING TABLES WITH THEIR FIBERS ORIENTED IN THE DIRECTION OF TRAVEL. THE TABLES ARE MOVED AROUND AN OVAL PATH WITH A CAM FOLLOWER SECURED AT THE LOWER END OF EACH TABLE RIDING AN AN OVAL CAM TRACK. THE CAM TRACK CAUSES EACH TABLE TO ROTATE 90* AS IT MOVES AROUND ONE END OF THE OVAL PATH SO THAT THE WEB FIBERS ARE ORIENTED TRANSVERSELY TO THEIR DIRECTION OF TRAVEL. TO PERMIT ROTATION OF ADJACENT TABLES WITH-   OUT INTERFERENCE, THE ENDS OF THE OVAL CAM TRACK ARE INCLINED SO THAT THE TABLES ARE SPACED VERTICALLY WITH RESPECT TO EACH OTHER DURING ROTATION. THE TRANSVERSELY ORIENTED WEBS ARE THEN SUCCESSIVELY REMOVED FROM THE MIVING TABLES AND CROSSLAID ON ANOTHER MOVING MEDIUM TO FORM A COMPOSITE NONWOVEN MATERIAL.

Jan. 16', 1973 w. H. BURGER CROSSLAYING MACHINE 3 Sheets-Sheet 2 Filed sept. z, 196e M. W y W Jin. 16, 1973 w, BURGER 3,711,354

CROSSLAYING MACHINE Filed Sept. 2, 1969 3 Sheets-Sheet 3 @F 7 y ./Z/

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| I: I jy /f ff United States Patent Office 3,711,354 Patented Jan. 16, 1973 3,711,354 CRSSLAYIN G MACHINE William H. Burger, Neenah, Wis., assignor to Kimberly-Clark Corporation, Neenah, Wis. Filed Sept. 2, 1969, Ser. No. 854,552 Int. Cl. B32b .i1/04, 31/18 U.S. Cl. 156-269 9 Claims ABSTRACT F THE DISCLOSURE A method for eiciently handling and crosslaying webs of substantially aligned light weight fibers in the production of nonwoven materials incorporating such crosslaid fibers for two-dimensional strength. Webs of substantially aligned fibers are deposited on individual moving tables with their fibers oriented in the direction of travel. The tables are moved around an oval path with a cam follower secured at the lower end of each table riding in an oval cam track. The cam track causes each table to rotate 90 as it moves around one end of the oval path so that the web fibers are oriented transversely to their direction of travel. To permit rotation of adjacent tables without interference, the ends of the oval cam track are inclined so that the tables are spaced vertically with respect to each other during rotation. The transversely oriented webs are then successively removed from the moving tables and crosslaid on another moving medium to form a composite nonwoven material.

DESCRIPTION OF THE INVENTION The present invention relates generally to nonwoven materials having crosslaid fibers and more particularly concerns an improved method and apparatus for making such nonwoven materials.

In the manufacture of nonwoven materials it is often desirable to apply bers in transverse directions to give two-dimensional strength to a composite material. In the past it has been difiicult to handle such fibers or webs of such fibers due to their light weight and fragile character.

It is a primary object of the present invention to provide an improved and efiicient method and apparatus for handling and crosslaying light-weight fibers in the production of a composite nonwoven material.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings, wherein:

FIG. l is a partially schematic elevation view of apparatus embodying the present invention;

FIG. 2 is a top view of the apparatus of the present invention taken in the plane of line 2-2 in FIG. l;

FIG. 3 is a vertical section taken in the plane of line 3 3 in FIG. l;

FIG. 4 is an enlarged fragmentary section taken in the plane of line 4 4 in FIG. 3;

FIG. 5 is a plan view of a finished material manufactured by the illustrated apparatus with sections of the individual layers broken away to show the multi-component construction.

While the invention is susceptible of various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but, on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention.

Turning now to the drawings, the invention is there exemplified in an apparatus for forming a nonwoven composite material having highly oriented crosslaid fibers therein. In the illustrative apparatus, multiple slivers 11 of textile fibers are drawn into a draw frame 12 which comprises a series of pairs of rolls 14 and 15. The rolls of each pair are driven by appropriate gearing well known to the art at a peripheral rate of speed faster than the rate of rotation of the preceding roll pair. As the juxtaposed slivers pass through the draw frame 12, the individual fibers are drafted and spread out t0 form a Ifiat striated web 20 of substantiallyk aligned fibers. The liber web 20 has a principal strength component, or direction of strength, in the direction of the fiber alignment, while it is substantially deficient in cross direction strength. While the illustrated method and apparatus will be described in connection with such highly drafted liber webs, it will be understood that other light weight fragile webs could similarly be employed.

In accordance with the present invention, the fragile web is successively deposited on the individual moving platforms with the web fibers oriented in the direction of the platform movement, the platforms are moved along a prescribed path, and each platform is rotated a determined angle as it is moved so that the web fibers are then oriented transversely to their direction of travel. In the illustrated embodiment, the web 20 is deposited on successive moving tables 21, each having a vertical post 22 and a horizontal platform 24, which are conveyed about an oval path by a pair of drive chains 25, 26. The drive chains 25, 26 each are trained about a pair of spaced sprockets 2S, 29 and 30, 31, respectively. The sprockets 28 and 30 are coaxially mounted on a vertical shaft 32, and the sprockets 29 and 31 are coaxially mounted on a vertical shaft 34 so that the rohains 25, 26 are disposed about their respective sprockets in parallel horizontal planes. The vertical shafts 32 and 34 are both rotatably mounted in a base 35 of the apparatus.

The post 22 of each table 21 is carried in a bearing sleeve 36 which is rigidly supported in spaced relation from the chains 25, 26 by means of two transversely extending arms 38, 39, respectively. The bearing sleeves 36, which each contain a pair of roller bearings 40, support the table posts 22 for both rotational and vertical movement relative to the sleeves and chains. An end cap 41 secures each bearing 40 within the sleeve 36.

To drive the chains 25, 26 the upper end of the sprocket shaft 22 carries another sprocket 49. A chain S0 connects the sprocket 49 to an output sprocket 51 of an appropriate drive motor 52. Operation of the drive motor 52 rotates the shaft 22, causing the chains 25, 26 to be driven about their respective pairs of sprockets and the tables 21 to be moved along with the chains. As shown in FIG. 2, the tables are thereby moved along a prescribed oval path 54 which is a uniform distance radially outward from the chains 25, 26. The oval path 54 of the tables in the illustrated case thus has generally straight sides 54a and 54e between the sprockets and curved ends 54b and 54d around the sprockets.

The lower end of each table post 22 has a transversely extending cam follower arm 55 rigidly secured thereto. The end of the cam follower arm 55 is provided with a depending pin 56 rotatably carrying a cam roller 58. As the tables are conveyed around the oval path 54, the cam roller 58 of each table 21 rides in a cam track 60 formed in the base 35. The cam track 60 is laid out in an oval shape corresponding generally to the oval path 54 of travel of the tables 21, having straight sides 60a and 60o and curved ends 60b, 60d.

As the tables 21 are conveyed along the straight side 54a of their path of travel, the table platforms 24 successively pass under the draw frame 12 so that the upper surface of each platform moves in close relation to a large draw frame roll 62. The web 20 is drawn out and deposited on the successive moving platforms 24 as they pass under the draw frame with the web fibers oriented thereon in their direction of travel. While moving along the side 54a of the oval path, the platforms 24 are in the same plane and are in abutting relation so that an uninterrupted platform surface is provided to receive the web 20. In the illustrated embodiment, the table platforms 24 are square shaped and the web 20 completely covers the platforms. It will become apparent, however, that other regular polygonal platform shapes may be used.

To aid in holding the web 20 in place on the moving table platforms 24, the upper surfaces of the platforms preferably have a pile fabric covering. An electrostatic charge may also be applied to the surface by an appropriate charger 6-4 to further insure that the web will be held firmly on the moving table. The web 20 thus is carried along by the tables 21 with the web fibers oriented in their direction of travel.

In carrying out the invention, as each moving table 21 reaches the curved end S4b of their oval path of travel, the table is rotated 90 so that the web fibers are oriented transversely to their direction of movement. Rotation of the tables 21 in the illustrated embodiment is effected by cam forces acting on the cam roller '8 and follower arm 55 as the roller rides in the cam track 60. Since the tables 21 have a set oval path of travel being affixed to the chains 25, 26, a variance in the location of the cam track 60 relative to the table path of travel S4 will cause the cam follower arm 55 and table post 22 to be rotated relative to the bearing sleeve 36 supporting the table. It will be apparent to one skilled in the art that various degrees of rotational movement may be effected by appropriately designing the layout of the cam track 60 relative to the oval path 54 of the tables travel. If another regular polygonal shape is chosen for the platforms, rather than a square shape illustrated, the angle of platform rotation preferably should be the quotient of 360 divided by the number of sides in the polygon, or any multiple thereof.

To permit rotation of each table platform 2-4 Without interference with the adjacent preceding and succeeding platforms, the tables are moved vertically with respect to each other so that they are disposed at different elevations as they proceed around the curved end 54h of the oval path and are rotated. To effect the vertical movement of the tables, the curved cam track end 60b is inclined so that the cam roller 58, follower arm 5S and table 21 are cammed upward by the track 60h as the table is moved around the end S419 of the oval path. As explained, the bearing sleeves 36 permit such vertical and rotational movement of the posts 22 with respect to the sleeves 36. v

Elevating the table platforms 24 relative to each other as the tables are moved around the curved end 54h of the oval also serves in the illustrated process to separate the fragile web 20 into discrete lengths 20a corresponding to the lengths of the platforms 24. Since the web bers are relatively short, the relative vertical movement of adjacent platforms will sever the web 20 with a substantially clean and even break. It will be appreciated, however, that if desired the web 20 could be cut into discrete lengths by an appropriate means before the lengths are placed on the table platforms.

In order to reduce the effects of centrifugal forces and wind forces on the webs 20a as they are rotated while being moved around the end54b of the oval path, the cam track 60 preferably should be designed to rotate the platforms in a direction opposite to the direction the platforms are conveyed around the oval 54. Thus, since the tables in the illustrated embodiment are moved in a clockwise direction around the oval path 54, the tables are rotated in a counterclockwise direction While pro-V After each table 21y has completed its travel around ceeding around the curved end 54h of the oval.

the end 54b of the oval path, and thus the inclined end 6tlb of the cam track, it proceeds along the straight sides 54p` and 60C of the oval path and cam tracks, respectively. The cam track side 60C is in a level plane but at a higher elevationv than the side 60a. As a result, as the tables 21 travel along the straight side 54C, the table platforms 24 again come into horizontal alignment and are in abutting relation so that an uninterrupted ply of web fibers, oriented transversely to their direction of travel, is presented for removal from the platforms.

In keeping with the invention, the transversely oriented webs are successively removed from the moving table platforms and are crosslaid on another moving medium to form a composite nonwovenl material. In the illustrated embodiment, the web lengths 20a are successively removed from the moving table platforms 24 by a suction' roll 70 disposed directly over the passing platforms 24, and the web lengths 20a are combined with an elongated carrier sheet 71. The carrier sheet 71, which may be a crepe wadding material stretched and ironed to faciall tissue softness, is drawn around the suction roll 70 from a supply roll 72. Between the supply roll 72 and suction roll 70, a metered amount of adhesive is applied to onel side of the carrier sheet 71 by means of an adhesive sprayer 74. As each table platform 24 is passed below the suction roll 70, suction pressure acts through the carrier sheet 71 to draw the web lengths 20a against the adhesively coated carrier sheet, with the web fibers oriented on the sheet transversely to its direction of travel. To facilitate removal of the web lengths 20a from the platforms, the platforms may be grounded by known means as they approach the suction roll 70 to nullify the electrostatic charge previously applied to the platform surface. Since the tables 21 are positioned immediately adjacent to each other as the tables pass the suction roll 70, a uniform ply of crosslaid fibers is applied to the carrier sheet. It will be appreciated that due to the very thin nature of the fiber webs any small amount of overlapping that may exist between the web lengths 20a will have no noticeable effect in the finished product.

In the illustrated embodiment, the carrier sheet 71 with the crosslaid web lengths 20a is next drawn past a draw frame 78 where a continuous fiber web 75 having fibers aligned in the direction of the web travel is applied over the crosslaid web lengths 20a. The continuous web 75 is formed by drawing multiple slivers 76 to textile fibers through the draw frame '78 in a manner similar to that described above. The web 7S is drawn around a large draw frame end roll 79 and deposited over the crosslaid fibers 20a as the carrier sheet 71 is drawn past the end roll 79.

To complete the composite material in the illustrated process, an elongated carrier sheet 80, similar to the crepe wadding carrier sheet 71, is applied over the continuous web 75. The carrier sheet 80 is drawn from a supply roll 81, and an adhesive is applied to one side of the sheet by an appropriate sprayer 82. The carrier sheet 80 and the carrier sheet 71 with the crosslaid webs 20a and 75 are then drawn between a pair of rolls 84 causing the fibers of the crosslaid webs 20a and 75 to be impinged against the adhesive surfaces of the sheets 70 and 80 and become partially imbedded therein, form ing a composite laminated sheet 85. The composite sheet may be passed through an appropriate heating means (not shown) where the adhesive is cured to a substantially non-tacky condition. After curing, the composite sheet 8'5 is drawn around a takeup roll 8-6. Referring to FIG. 5, the finished composite material S5 includes the outer carrier sheet 80, the web 75 having bers oriented in the longitudinal direction of the composite material, the crosslaid webs 20a having transversely oriented fibers, and the outer carrier sheet T1.

After the web lengths 20a have been removed from the moving table platforms 24, the tables proceed around the curved endk 54d of the oval path and 60d of they cam track and return to their starting point to repeat the cycle. The curved end 60d of the cam track declines from the elevated level of the side 60C to the lower level of the side 60a, causing the platforms to be vertically spaced with respect to each other to permit turning and rotation of the platforms without interference as they proceed around the curved end 54d. In the illustrated embodiment, the platforms 24 are again rotated 90 as they proceed around the end 54d by the camming action of the cam track 60d on the follower roller 58 and arm S. Table rotation in this case is in the same direction as the travel of the tables around the oval since the tables are not carrying the web so that Wind and centrifugal forces are of less concern. It will be apparent to one skilled in the art that if the table platforms are square, as in the illustrated case, it is not essential that the empty tables again be rotated with respect to their line of travel as they proceed around end 54d. It is only important that the platforms 24 be in alignment and in abutting relation as they proceed along the side 54a of the oval path to again receive the ber web 20.

In view of the foregoing, it can be seen that the apparatus and method of the present invention provides an efficient and reliable means of handling and crosslaying light-weight web bers in the production of a composite nonwoven material. It will be apparent to those skilled in the art that many variations from the examples given may be employed without departing from the spirit of this invention. For example, slivers introduced into the draw frames 12 and 78 may include thermoplastic bers which, when heated, bond together. Also, other types of oriented webs, especially webs which are deficient in cross direction strength, such as creped tissue, carded Webs, spread tow, plastic films or split lm networks, highly oriented in the direction of travel, may be substituted for the highly drafted ber web if desired.

I claim as my invention: 1. A method of crosslaying continuous webs of longitudinally oriented fibers and forming a nonwoven material therefrom, comprising the steps of:

moving a rst of said continuous webs longitudinally along a prescribed path, the principal strength cornponent of the web being oriented substantially in the direction of its travel along said path;

transversely severing said first web into a number of discrete, generally -flat lengths; rotating said generally at lengths a predetermined angle such that said lengths are transversely positioned relative to said path and arranged in substantially edge to edge abutting relationship to form a continuous layer;

superposing a second of said continuous webs upon said layer of rotated lengths, the principal strength component of said second web being oriented substantially in the direction of its travel; and

bonding said layer of rotated lengths and said second continuous web together to form a self-sustained nonwoven crosslaid material.

2. The method of claim 1 wherein said rst web is carried by a surface comprised of a number of individual separable and rotatable platforms.

3. The method of claim 2 in which said platforms are moved around an oval path, and said platforms are successively rotated as each platform travels around one end of said oval path.

4. The method of claim 3 in which said platforms are rotated in a direction opposite to the direction said platforms travel around said oval path.

5. The method of claim 2 in which said platforms have a rectangular shape, and including the steps of moving said platforms in a line over a portion of said prescribed path with one platform being immediately adjacent to the preceding and succeeding platforms to provide a substantially uninterrupted surface upon which said web may be deposited, and moving each platform vertically with respect to said adjacent platforms to permit rotation of said platform without interference with said adjacent platforms.

6. The method of claim 2 in which said platforms are moved in a line over a portion of said prescribed path with one platform being immediately adjacent to the preceding and succeeding platforms, and said web is an elongated uninterrupted ply of material which is deposited on said moving adjacent platforms without separation into individual lengths, and said platforms each moved vertically relative to the adjacent platforms while moving along another portion of said prescribed path to separate said web into discrete lengths corresponding substantially to the lengths of the individual platforms.

7. The method of claim 2 including electrostatically charging each said platform to securely retain said web on said platform as said web is carried along said prescribed path by said platform.

8. The method of claim 2 in which each said platform is rotated approximately With respect to its direction of travel.

9. The method of claim 2 including successively combining said webs with a moving medium after removal from said platforms with said web strength components oriented transversely to the direction of travel of said medium.

References Cited UNITED STATES PATENTS 3,236,711 2/19'66 Adler 156-25 UX BENJAMIN A. BORCHELT, Primary Examiner J. V. DORAMUS, Assistant Examiner U.S. Cl. X.R. 156--36'2, 556, 568 

